The present invention relates generally to methods and apparatus for increasing the pressure of cooling fluid utilized within a gas turbine engine. More particularly, one embodiment of the present invention relates to an internal pump coupled to a turbine disk for pressurizing compressor discharge working fluid to be utilized in cooling the combustor discharge nozzle.
A common technique for cooling gas turbine engine components, such as the combustor discharge nozzle, is to utilize a portion of the air from the compressor as a cooling fluid. In many systems, compressor discharge air flows from the compressor through the diffuser, bypasses the combustor liner, and is delivered to the combustor discharge nozzle. The cooling fluid flows within an internal passageway within nozzle components to remove heat through convective heat transfer.
Engineers and scientists continue to develop many engine designs to meet the demands of modern propulsion systems. In some designs, there is a significant reduction in the combustion system pressure loss. This minimization of combustion system pressure loss can make it challenging to maintain an adequate pressure differential at the combustor discharge nozzle to allow the needed flow to cool the components. Further, in some engine designs, there is a drastic increase in the temperature of the compressor discharge air due to higher-pressure ratios and/or the operation of the aircraft at higher air speed. It is recognized that passing it through a heat exchanger can reduce the temperature of the compressor discharge air. Each of these designs is generally limited by the ability to supply cooling fluid having the pressure necessary to be driven through the cooling circuit and to eliminate the occurrence of backflow.
The present application meets the need for increasing the pressure of cooling fluid utilized within a gas turbine engine in a novel and non-obvious way.